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Sphaeropleales Genera
Sphaeropleales is an order of green algae that used to be called Chlorococcales. The order includes some of the most common freshwater planktonic algae such as '' Scenedesmus'' and '' Pediastrum''. The Sphaeropleales includes vegetatively non-motile unicellular, colonial , or filamentous taxa. They have biflagellate zoospores with flagella that are directly opposed in direction (the DO arrangement): '' Sphaeroplea'', '' Atractomorpha'', '' Neochloris'', '' Hydrodictyon'', and '' Pediastrum''. All of these taxa have basal body core connections. Motile cells generally lack cell walls or have only a very fine layer surrounding the cell membrane. Other common characteristics include a robust vegetative cell wall, cup-shaped chloroplasts with large pyrenoids, and relatively large nuclei. With an increase in the number of taxa for which sequence data are available, there is evidence of an expanded DO clade that includes additional zoosporic ('' Bracteacoccus'', '' Schroederia'') an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pediastrum Duplex
''Pediastrum duplex'' is a species of fresh water green algae in the genus ''Pediastrum''. It is the type species of the genus ''Pediastrum''. ''Pediastrum duplex'' forms nonmotile coenobia (colonies) with a fixed number of cells. These coenobia are flat and have a circular shape. The colonies usually contain 8 to 32 cells, with examples of 4, 64 or 128 occurring rarely. Colonies have holes between the cells; the holes are smaller in diameter than the cells. The cells are polygonal, distinctly rectangular in outline with concave sides. The outer cells of the coenobium have two triangular lobes that are longer than the cell body. At the tip of the lobes are very short rosettes that may also have fine bristles. The cell wall is usually smooth, but may sometimes have a distinct sculptured texture. It reproduces by forming autocolonies asexually, although sexual reproduction has also been observed. ''Pediastrum duplex'' is a very common component of the freshwater phytoplankton, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pediastrum
''Pediastrum'' is a genus of green algae, in the family Hydrodictyaceae. It is a photoautotrophic, nonmotile coenobial green alga that inhabits freshwater environments. The name ''Pediastrum'' comes from the Greek root words ''pedion'', meaning "plane", and ''astron'', meaning "star", referring to its overall shape. Morphology ''Pediastrum'' develops colonies with a fixed number of cells, termed coenobia. In this case, the coenobia are composed of between 22 and 27 cells, which are orderly arranged in a flat disk. The diameter of a single coenobium ranges from 20 to 80 μm, making them microalgae. Cells in ''Pediastrum'' are dimorphic, consisting of interior cells and peripheral cells, distinguished by their position in the colony and by their shape. Some species have inter-cellular spaces between their interior cells. The peripheral cells surround the interior cells, and they usually possess bristles, V-like cutting edges, or wavy projections. ''Pediastrum'' shows lots of m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scenedesmus
''Scenedesmus'' is a genus of green algae, in the class Chlorophyceae. They are colonial and non-motile. They are one of the most common components of phytoplankton in freshwater habitats worldwide. Taxonomy The starting point of ''Scenedesmus'' and related algae is in 1820, when Pierre Jean François Turpin observed these algae under a microscope. He classified them under the diatom genus '' Achnanthes''; later authors moved them to different groups, until it was finally classified as a green alga. The name comes from the Greek roots ''skene'', meaning "tent" or "awning", and ''desmos'', meaning "bond". Currently, there are 74 taxonomically accepted species of ''Scenedesmus''. Additionally, several subgenera have been identified, but vary according to the source. Hegewald denotes ''Acutodesmus'', '' Desmodesmus'', and ''Scenedesmus'' as the three major categories. ''Acutodesmus'' is characterized as having acute cell poles, while ''Desmodesmus'' and ''Scenedesmus'' have obtuse/t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plankton
Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucial source of food to many small and large aquatic organisms, such as bivalves, fish, and baleen whales. Marine plankton include bacteria, archaea, algae, protozoa, microscopic fungi, and drifting or floating animals that inhabit the saltwater of oceans and the brackish waters of estuaries. fresh water, Freshwater plankton are similar to marine plankton, but are found in lakes and rivers. Mostly, plankton just drift where currents take them, though some, like jellyfish, swim slowly but not fast enough to generally overcome the influence of currents. Although plankton are usually thought of as inhabiting water, there are also airborne versions that live part of their lives drifting in the at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chlorococcales
Chlorococcales is a formerly recognized Order (biology), order of green algae in the Class (biology), class Chlorophyceae. , the type family Chlorococcaceae was placed in the order Chlamydomonadales. Conventionally, many groups of coccoid green algae were lumped in the order Chlorococcales sensu lato by Komárek & Fott (1983), based on Pascher's (1918) idea of establishing orders according to life forms. However, coccoid green algae are currently placed in several orders of Chlorophyceae, Trebouxiophyceae, Ulvophyceae (e.g., ''Chlorocystis'') and Prasinophyceae within the division Chlorophyta, or in the division Charophyta (e.g., Chlorokybales, Desmidiales). Families According to Komárek & Fott (1983): * Chlorococcaceae (Chlorococcoideae, Spongiococcoideae) * Palmellaceae (Hormotiloideae, Palmelloideae, Neochloridoideae, Chlorosarcinoideae) * Chlorochytriaceae * Dicranochaetaceae * Characiaceae (Fernandinelloideae, Characioideae, Schroederioideae) * Treubariaceae * Golenki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Green Alga
The green algae (: green alga) are a group of chlorophyll-containing autotrophic eukaryotes consisting of the phylum Prasinodermophyta and its unnamed sister group that contains the Chlorophyta and Charophyta/ Streptophyta. The land plants ( Embryophytes) have emerged deep within the charophytes as a sister of the Zygnematophyceae. Since the realization that the Embryophytes emerged within the green algae, some authors are starting to include them. The completed clade that includes both green algae and embryophytes is monophyletic and is referred to as the clade Viridiplantae and as the kingdom Plantae. The green algae include unicellular and colonial flagellates, most with two flagella per cell, as well as various colonial, coccoid (spherical), and filamentous forms, and macroscopic, multicellular seaweeds. There are about 22,000 species of green algae, many of which live most of their lives as single cells, while other species form coenobia (colonies), long filaments, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Order (biology)
Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized by the nomenclature codes. An immediately higher rank, superorder, is sometimes added directly above order, with suborder directly beneath order. An order can also be defined as a group of related families. What does and does not belong to each order is determined by a taxonomist, as is whether a particular order should be recognized at all. Often there is no exact agreement, with different taxonomists each taking a different position. There are no hard rules that a taxonomist needs to follow in describing or recognizing an order. Some taxa are accepted almost universally, while others are recognized only rarely. The name of an order is usually written with a capital letter. For some groups of organisms, their orders may follow consist ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polyedriopsis
''Polyedriopsis'' is a genus of green algae in the order Sphaeropleales. , it contained a single species, ''Polyedriopsis spinulosa''. It is found worldwide in freshwater habitats as phytoplankton, but is rare. ''Polyedriopsis spinulosa'' consists of solitary or sometimes clustered cells, 12–25 μm in diameter. They are four- or five-sided with concave sides; the corners are rounded off and bear a tuft of 3-10 thin tapering spines, 25–50 μm long. Cells are uninuclate (with one nucleus and contain a single parietal chloroplast with one pyrenoid. ''Polyedriopsis spinulosa'' reproduces asexually via the formation of zoospores, of which 4 to 8 are produced per cell. Zoospores are ovate, with two flagella A flagellum (; : flagella) (Latin for 'whip' or 'scourge') is a hair-like appendage that protrudes from certain plant and animal sperm cells, from fungal spores ( zoospores), and from a wide range of microorganisms to provide motility. Many pr ... and a stigma. Referenc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incertae Sedis
or is a term used for a taxonomy (biology), taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty at specific taxonomic levels is indicated by (of uncertain family), (of uncertain suborder), (of uncertain order) and similar terms. Examples * The fossil plant ''Paradinandra, Paradinandra suecica'' could not be assigned to any family, but was placed ''incertae sedis'' within the order Ericales when described in 2001. * The fossil ''Gluteus minimus (fossil), Gluteus minimus'', described in 1975, could not be assigned to any known animal phylum. The genus is therefore ''incertae sedis'' within the kingdom Animalia. * While it was unclear to which order the New World vultures (family Cathartidae) should be assigned, they were placed in Aves ''incertae sedis''. It was later agreed to place them in a separate order, Cathartiformes. * Boc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
